Masu fasa da'irar akwati da aka ƙera su ne na'urorin kariya na lantarki waɗanda aka ƙera don kare da'irar lantarki daga wuce gona da iri. Wannan wuce gona da iri na iya faruwa ne saboda yawan aiki ko gajeriyar da'ira. Ana iya amfani da masu fasa da'irar akwati da aka ƙera a cikin nau'ikan ƙarfin lantarki da mitoci iri-iri tare da ƙayyadadden iyaka na ƙasa da sama na saitunan tafiya masu daidaitawa. Baya ga hanyoyin tuntuɓewa, ana iya amfani da MCCBs azaman maɓallan katsewa da hannu idan akwai gaggawa ko ayyukan gyara. Ana daidaita MCCBs kuma ana gwada su don overcurrent, ƙarfin lantarki, da kariyar lahani don tabbatar da aiki lafiya a duk mahalli da aikace-aikace. Suna aiki yadda ya kamata azaman maɓalli na sake saitawa don da'irar lantarki don cire wutar lantarki da rage lalacewa da yawan aiki da'ira, matsalar ƙasa, gajerun da'ira, ko lokacin da wutar lantarki ta wuce iyakokin yanzu.
CJ:Lambar Kasuwanci
M: Mai karya da'irar akwati mai ƙira
1:Lambar Zane
□:Matsayin wutar lantarki na firam
□: Lambar halayyar ƙarfin da ke karya/S tana nuna nau'in da aka saba (S za a iya cire shi) H tana nuna nau'in da ya fi girma
Lura: Akwai nau'ikan sandar tsaka-tsaki guda huɗu (N) don samfurin matakai huɗu. Sandar tsaka-tsaki ta nau'in A ba ta da abubuwan da ke haifar da cunkoso fiye da kima, koyaushe tana kunnawa, kuma ba a kunna ta ko kashe ta tare da sauran sandunan uku ba.
Sandar tsaka tsaki ta nau'in B ba ta da sinadarin juyawar wutar lantarki mai yawa, kuma ana kunna ta ko kashe ta tare da wasu sanduna uku (ana kunna sandar tsaka tsaki kafin a kashe ta). Sandar tsaka tsaki ta nau'in C tana da sinadarin juyawar wutar lantarki mai yawa, kuma ana kunna ta ko kashe ta tare da wasu sanduna uku (ana kunna sandar tsaka tsaki kafin a kashe ta). Sandar tsaka tsaki ta nau'in D tana da sinadarin juyawar wutar lantarki mai yawa, koyaushe ana kunna ta kuma ba a kunna ta ko kashe ta tare da sauran sanduna uku.
| Sunan kayan haɗi | Fitowar lantarki | Sakin mahadi | ||||||
| Taimakon lamba, a ƙarƙashin sakin ƙarfin lantarki, alamar lamba | 287 | 378 | ||||||
| Saiti biyu na tuntuɓar taimako, lambar ƙararrawa | 268 | 368 | ||||||
| Sakin rufewa, lambar sadarwa ta ƙararrawa, lambar sadarwa ta taimako | 238 | 348 | ||||||
| A ƙarƙashin sakin ƙarfin lantarki, lambar ƙararrawa | 248 | 338 | ||||||
| Lambar ƙararrawa ta taimako | 228 | 328 | ||||||
| Lambar wayar ƙararrawa ta shunt release | 218 | 318 | ||||||
| Sakin ƙaramin ƙarfin lantarki na ƙarin hulɗa | 270 | 370 | ||||||
| Biyu taimako lamba sets | 260 | 360 | ||||||
| Sakin Shunt a ƙarƙashin sakin ƙarfin lantarki | 250 | 350 | ||||||
| Taimakon sadarwa na cirewar shunt release | 240 | 340 | ||||||
| Sakin ƙasa da ƙarfin lantarki | 230 | 330 | ||||||
| Taimakon taimako | 220 | 320 | ||||||
| Rufe sakin | 210 | 310 | ||||||
| Lambar tuntuɓar ƙararrawa | 208 | 308 | ||||||
| Babu kayan haɗi | 200 | 300 | ||||||